1. Field of the Art
This invention relates to the production of cysteamines and/or cystamines.
Cystamines are readily formed by oxidation of their corresponding cysteamines as in the example indicated in the following formula (1). Conversely, cysteamines are readily formed by reduction of their corresponding cystamines. ##STR1##
Since the oxidation or reduction as indicated in Formula (1) readily progresses even in vivo, these cysteamine and cystamine compounds are attracting much attention as medicinal substances exhibiting various physiological activities. For example, a cysteamine and certain related compounds are useful as substances having protective action relative to harmful effects of radiation.
Accordingly, there have been numerous proposals relating to the production of these compounds.
2. Prior Art
I have previously proposed a process (as disclosed in Japanese Patent Publication No. 3365/1978) for producing cysteamines by heating and reacting an aminoalkyl sulfate ester and a compound having hydrogen sulfide ions (.sup..crclbar. SH). This prior invention succeeded in producing cysteamines with greater facility and higher yield than processes previously known at that time by heating an aminoalkyl sulfate ester and a hydrogen sulfide such as ammonium hydrogen sulfide or potassium hydrogen sulfide in a solvent such as water or water-containing alcohol.
It was discovered, however, that a problem is sometimes encountered in the practice of this prior invention in that, when an alkali hydrogen sulfide such as potassium hydrogen sulfide or sodium hydrogen sulfide is used as a source of the hydrogen sulfide ions, thioethers are easily formed as accompanying by-products in addition to the cysteamines and/or cystamines depending on the reaction conditions.